DE102006049616B4 - Arrangement of an aerodynamic component with a slotted rear or side edge in a flow - Google Patents

Abstract

Arrangement of an aerodynamic component in a flow, wherein the component has a turbulent overflowed in an overflow edge on which two major surfaces of the component abut each other and divide the flow or merge two separate partial flows to the flow, wherein the component in the region of the edge with slots having a slot length of the slots between 1 and 10 cm, characterized in that the slots (3) extend from the one main face (4) to the other main face (5 th) ) with in the overflow direction (U) and above the respective slot height of the slot (3) between the two main surfaces (4, 5) of constant slot width (s) between 0.05 mm and 0.5 mm through and that a slot spacing (a) the slots (3) with each other is not greater than 10 times the slot width (s) of the slots (3).

Description

TECHNICAL FIELD OF THE INVENTION

The The invention relates to an arrangement of an aerodynamic Component in a flow, having the features of the preamble of independent claim 1 and in the one edge, on the two main surface of the component together bump and the flow divide or merge two separate streams to the flow, is overflowed turbulent.

at the turbulent overflowed edge in particular, it is a trailing or trailing edge of the aerodynamic component; It can also be a turbulent overflowed side or even a turbulent overflowing front or inflow edge act of the component.

At to hit the edge two main surfaces of the component to each other. These main surfaces are in the Usually around a positive pressure side and a negative pressure side of the component. The present invention but is also applicable if there are no pressure differences.

Concrete It is in the present invention to reduce the sound radiation of aerodynamic components in which edges are overflowed turbulently. Under one edge of an aerodynamic component becomes a kinky Geometry element on the flow around understood aerodynamic component, the sharp-edged, dull or may be rounded and at the two major surfaces of the component in such a way bump, that a flow divided or two separate streams are merged into a flow.

STATE OF THE ART

Of the turbulent overflow trailing edges aerodynamically generated sound represents a very significant part of the sound radiation flowed around aerodynamic components. Produce this trailing edge noise dominant noise levels such as high-lift flaps on aircraft wings, fan blades, wind turbines, etc. The physical relationships in the formation of trailing edge noises are first described by Ffowcs-Williams, J. E .; Hall, L. H .: "Aerodynamic sound generation by turbulent flow in the vicinity of a scattering helped plans", J. Fluid Mech. (1970); vol. 40, part 4, pp. 657-670 Service. The intensity of the sound emerging at the trailing edge is then on the one hand dependent from the intensity the turbulent speed fluctuation in the immediate Near the Trailing edge. On the other hand, determines the design of the trailing edge even the degree of implementation of turbulent speed fluctuations in sound.

In the EP 1 314 642 B1 It is disclosed that considerable noise reduction can be achieved by having a row of brushes attached to the trailing edge when the individual bristles of the row of brushes are aligned along the main flow and point downstream of the trailing edge. Detailed parameter studies on this are provided by Herr, M., and Dobrzynski, W .: "Experimental Investigations in Low Noise Trailing-Edge Design," AIAA Journal, 43, 6, (2005), pp. 1167-1175, June 2005 Service. In particular, non-flexible bristles have yielded a reduction. The main effect of the bristles is believed to be a gradual damping of the turbulent velocity variations in the direction of flow. A similar reduction in noise has also been achieved with components made at least in part of porous materials, such as at the flap side edge or the turbulently inflated flap leading edge.

Conditional successes have also been with serrated trailing edges as seen from the US 5 088 665 A are known achieved.

An arrangement of an aerodynamic component in a flow with the features of the preamble of claim 1 is known from EP 1 112 928 A2 known. Here, the trailing edge is angled or thickened relative to the upstream profile of the component in the direction of flow towards the negative pressure side. In the area of the thickening, slits are introduced from the negative pressure side. The length of the slots should not exceed about 3% to 5% of the tread depth of the aerodynamic component. The proportion of the slot depth with respect to the height of the trailing edge should be adjusted accordingly to the vortex formation and not exceed a level of about 8% of the tread depth. The slots are provided along the profile edge in comparatively large distances and in turn also comparatively wide. However, this arrangement is neither intended nor suitable for reducing turbulence-related edge noise. From the EP 1 112 928 A2 aerodynamic components are also known in which macroscopic slots are provided in the region of the thickened Hinterkannte, which are overflowed in the transverse direction.

From the DE 1 169 303 B is a Querertriebsfläche, in particular lifting surface for aircraft, known with slots. The slots are those that z. B. are formed in the arrangement of slats or flaps and extending in the spanwise direction. These are macroscopic slots, which are aligned transversely to the overflow of the transverse drive surface. The slot width of the slots decreases from the pressure side the transverse drive surface on the suction side down. The and on the pressure side lying inflow openings of the slots are covered at least over part of their spanwise extension by a perforated surface, the openings of which release a cross section which is larger in area than the cross section of the associated outflow opening of the slots.

From the DE 434 540 A An aircraft wing is known having slots perpendicular to the rear and side edges. The slots formed by solid material have a tapered cross-section and extend at the rear edge of the aircraft wing from the bottom center to the side wing ends up parallel to the direction of flight and at the side wing ends from bottom back to front top perpendicular to the direction of flight. There is no question of a turbulent overflow of the rear edge of an aircraft wing, which thus has macroscopic slits.

From the DE 420 325 A is a device for damping edge vortices on aircraft wings and the like. Known, are provided in the rear part of the wings in any number and size in the direction of movement extending slots, each of which extends from the front to the rear. The slots shown in the figures of this document have macroscopic dimensions.

On the DE 248 599 A is an airfoil with automatic stabilization single bearing surfaces for aircraft and the like. Known, in which the rear part of the wing is divided into several smaller swingable individual wings. The individual wings are separated by slots that widen to the rear, and some of the individual wings are provided with vertical transverse walls on the inward edges. The air pressure constantly occurring from below against the wing pushes the air upwards through the slots, thereby eliminating the detrimental effect of air swirls occurring on the support ribs and other resistors. Wind gusts on the wing should be mitigated by the fact that the individual bearing surfaces are met with the vertical transverse walls of a crosswinds most effective and bent down according to the respective wind pressure, whereby the air flows through the more or less enlarged slots between the individual wings down.

From the US 2003/0201367 A1 For example, an airfoil is known which has slits extending in the spanwise direction in its main side forming its overpressure side. Air should be passed through the slots to prevent turbulence.

From the US 2,163,655 A Slits are known in a wing of an aircraft, which extend transversely to the overflow of the wing and have a decreasing from the pressure side to the pressure side of the wing airing.

From the WO 03/089295 A2 It is known to provide the outer skin of an aerodynamic component with slots of a length of 100 to 300 microns and a width of 50 to 250 microns, which slots may be aligned in the overflow direction of the component. Air is drawn in from the boundary layer of a surface of the aerodynamic component via the slots by means of a vacuum generator. The depth of the slots extends only over the outermost outer skin of the aerodynamic component.

OBJECT OF THE INVENTION

Of the Invention is based on the object, an arrangement of an aerodynamic Component in a flow to show with the features of the preamble of patent claim 1 in which the sound radiation from the turbulent overflowed edge significantly reduced is, without it being necessary, the edge for attaching brushes thicker than aerodynamically desired form and brushes to be attached to the edge or replaced according to their wear, component integration into an adaptive system is not a disadvantage opposite one usual execution and minimizes aerodynamic disadvantages when used on lifting surfaces stay.

SOLUTION

According to the invention Task by an arrangement of an aerodynamic component in one flow solved with the features of claim 1. Preferred embodiments of the new arrangement are in the dependent claims 2 to 6 defined.

DESCRIPTION OF THE INVENTION

In the new arrangement of an aerodynamic component in a flow, the slots in the region of the turbulent overflowed edge of the aerodynamic component run continuously from one major surface to the other major surface of the component, which abut one another in the edge. In contrast to brushes, the slots can also be provided without problems on other turbulent edges, ie leading edges and laterally flowed-around edges (so-called side edges) of aerodynamic components. The use of the slots is also not limited to flat-like edges with low tapering angle, but largely any. In contrast to attached brushes, the slots in the new aerodynamic component are also wear-free and low-maintenance. It is at best to ensure that the slots are not clogged by impurities.

effects on the aerodynamic performance of the aerodynamic component due to the slits are not expected, other than this Orthmann, J .; Wild, J .: "Impact on the aerodynamics by acoustic measures on the wings "; lecture DAGA 2006, TU Braunschweig, in the conference proceedings of the DAGA 2006 for the aerodynamic Performances with brushes provided slat is known. Unlike brushes with bristles or needles of circular cross-section remain between the slots webs with rectangular cross-section, the edges of a well-defined surface current direction force and thus the degrees of freedom of unwanted turbulent flow fluctuations limit.

moreover becomes a potentially turbulence enhancing, the desired noise reduction counteracting receding Grading at the transition the edge on bristles or needles of a brush avoided. Nevertheless, will be the for to brush Proven noise reduction achieved with the new aerodynamic component. When brushing results the noise reduction probably from the friction damping the turbulent flow fluctuation in the very narrow columns, which is the smallest distance between give the juxtaposed bristles. The slots in the new aerodynamic component increase this friction effect their larger extension (Slot height) between the main surfaces of the aerodynamic component forming the edge. As well as edges with brushes avoid slotted edges not only broadband sound, but also tonal, hiebtonartige shares, as they are z. B. on turbulent overflowed blunt Trailing edges occur because the slots are the coherence of the flow fluctuations Destroy in the edge direction. The slots change the overall geometry of each edge is not. The shape of the edge remains overall, which in particular for adaptive elements, the slats, be essential can.

The Slot width of each slot in the new arrangement is at each Constant over the respective slot height of the slot. It should be achieved no nozzle effects here. Rather, it comes to the friction for the turbulent Strömungsfluktuationen in the slots.

The Slits can be open at the respective edge, so that the immediate edge only formed by the left between the slots webs becomes. The slots can on the edge but also be closed to the stability of the edge and the rigidity of the individual webs from between the slots to increase the material left over.

All Preferably, the slots are in the new aerodynamic component in the overflow direction aligned to the turbulent overflowed edge. They reach their highest Efficiency, because relevant shares of the flow casually into the slots which dampens their turbulent flow fluctuations.

Next the constant slot width over the respective slot height have the slots also in the overflow direction the edge has a constant slot width. This slot width of Specifically, slots can be between 0.05 mm and 0.5 mm. she should be much smaller than a correlation length formed in the edge direction the edge overflowing turbulence.

The Slots are in the overflow direction the edge aligned parallel to each other. A slot spacing of Slits among each other is not larger than 10 times, preferably not bigger than that 5 times the slot width of each slot. Neither must the slot widths of all slots still be constant their distances. You can rather to the local Be adapted particular features especially a longer edge.

From Slit planes defined by the slots may but need not be perpendicular to the main surfaces of the component, which collide at the respective edge. One The angle between the slit planes and the major edge-forming surfaces should be but at least 45 °. An oblique Employment of the slit planes against the edge-forming main surfaces is z. B. makes sense, if this makes a better adaptation to the Direction of the turbulent overflow of the Edge is achieved.

The slot length lies in a range of 1 to 10 cm. In any case, the should slot length the slots be bigger than, preferably more than twice the correlation length of Turbulence along the direction of the slots in the edge-forming main areas of the component.

Advantageous developments of the invention will become apparent from the claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the introduction to the description are merely exemplary and can come into effect alternatively or cumulatively, without the advantages having to be achieved by embodiments according to the invention. Further Merk The drawings - in particular the illustrated geometries and the relative dimensions of several components to one another and their relative arrangement and operative connection - can be seen in the drawings. The combination of features of different embodiments of the invention or of features of different claims is also possible deviating from the chosen relationships of the claims and is hereby stimulated. This also applies to those features which are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different claims. Likewise, in the claims listed features for further embodiments of the invention can be omitted.

BRIEF DESCRIPTION OF THE FIGURES

The Invention will be described below with reference to preferred embodiments explained and described in detail shows

1 a perspective view of the trailing edge of an aerodynamic component according to the invention.

2 a longitudinal section through the trailing edge in the region of a slot according to 1 ,

3 - 5 Longitudinal sections through various modifications of the slotted trailing edge of the aerodynamic component according to the invention according to the 1 and 2 ; and

6 a perspective view of a slotted side edge of an aerodynamic component according to the invention.

DESCRIPTION OF THE FIGURES

The in the 1 and 2 shown trailing edge 1 an aerodynamic component 2 is with slots 3 provided in the direction of a turbulent flow U of the trailing edge 1 run. This is a slot plane of the slots 3 described by a direction vector e _a of Kantenzu- or -abströmung and e _n , a 90 ° rotated by e _a direction vector e _k , along the trailing edge 1 runs. It is also a tilt of the thus defined cutting plane E of the slots 3 permissible by e _a of up to +/- 45 °, such that the direction vector e _n defining the slot plane would result in a 45 ° to 135 ° turn of e _k around e _a . A slot width s of the slots is much smaller than the correlation length of the trailing edge 1 overflowing turbulence in the edge direction e _k . For typical applications, it is between 0.05 and 0.5 mm. A slot spacing a between each slot, the width of the slots between the slots 3 standing bridges are determined, is to be chosen as low as possible, ie as small as structurally feasible. At least it should not be much larger than 5 to 10 times the slot width s. A slot length l should be significantly larger than a correlation length of the trailing edge 1 be overflowing turbulence in the flow direction U. This run length along the slots 3 is needed to gradually reduce the turbulent fluctuations. The front end of the slots can, as in 1 and 2 is shown, perpendicular to one of the edge-forming major surfaces 4 . 5 of the aerodynamic component, which is a negative pressure side 14 is. As the 3 and 4 suggest, but here also another course can be provided. So everyone can slot 3 forward on both edge-forming major surfaces 4 and 5 of the aerodynamic component 2 leak. The slots 3 also do not have to the extreme trailing edge 1 pass. You can rather in front of this outermost trailing edge 1 end, as in 5 Outlined is the influence of the slots 3 on the stability of the trailing edge 1 to limit.

6 outlines the slots according to the invention 3 on one side edge 6 an aerodynamic component 2 , The slots 3 Do not run perpendicular to the side edge here 6 but so to the side edge 6 employed, as is the turbulent flow U of the side edge 6 equivalent. If necessary, ie when occurring sound generation due to turbulent flow over the slots 3 also in the front edge 7 of the aerodynamic component 2 be provided.

1

trailing edge

2

component

3

slot

4

main area

5

main area

6

side edge

7

leading edge

14

Vacuum side

15

Pressure side

Claims (6)

Arrangement of an aerodynamic component in a flow, wherein the component has a turbulent overflowed in an overflow edge on which two major surfaces of the component abut each other and divide the flow or merge two separate partial flows to the flow, wherein the component in the region of the edge with slots is provided, which are aligned in the overflow direction of the edge parallel to each other, and wherein a slot length of the slots is between 1 and 10 cm, characterized in that the slots ( 3 ) from one main surface ( 4 ) except for the other main surface ( 5 ) with in the overflow direction (U) and above the respective slot height of the slot ( 3 ) between the two main surfaces ( 4 . 5 ) have a constant slot width (s) between 0.05 mm and 0.5 mm and that a slot spacing (a) of the slots ( 3 ) not greater than 10 times the slot width (s) of the slots ( 3 ). Arrangement according to claim 1, characterized in that the slots ( 3 ) on the edge ( 1 . 6 . 7 ) open leak. Arrangement according to claim 1, characterized in that the slots ( 3 ) on the edge ( 1 . 6 . 7 ) shut down closed. Arrangement according to one of claims 1 to 3, characterized in that an angle between the slots ( 3 ) defined slot planes and the main surfaces ( 4 . 5 ) is at least 45 ° and at most 135 °. Arrangement according to one of claims 1 to 4, characterized in that the slot spacing (a) of the slots ( 3 ) not greater than 5 times the slot width (s) of the slots ( 3 ). Arrangement according to one of claims 1 to 5, characterized in that a slot length (l) of the slots (1) 3 ) greater than a correlation length of turbulence in the direction of the overflow of the edge ( 1 . 6 . 7 ).